In:

1
In

• The purpose of the interactive notebook is to
  help you become more organized. List three things
  about the notebook that help accomplish this goal.

2
Chapter 1 The Nature of Chemistry
3
Chapter 1-1

• Chemistry the study of all substances and the
  changes that they can undergo.

4
The Scientific Method
Chapter 1-2

• Scientific method A six step systematic
  approach to gathering knowledge in order to
  answer questions.

5

• OBSERVATION a fact that is noticed either
  qualitatively or quantitatively
• QUESTION something that is asked in order to
  gain knowledge
• HYPOTHESIS a proposed, but unproved,
  explanation of observed facts an educated guess
• EXPERIMENT a carefully devised procedure for
  making observations and gathering data
• CONCLUSION a judgment or opinion formed as a
  result of analyzing experimental data

6

• Natural law describes HOW nature behaves but
  NOT WHY nature behaves that way
• Theory explains WHY natures behaves in the way
  described by the natural law

7
Units of Measurement
Chapter 1-4

• In order for a measurement to be correct, you
  must have a NUMBER and a UNIT.

Example 6 ? number by itself is meaningless
six what? 6 grams ? number now has
significance it is defined by the unit

• Derived unit a combination of base units
• Example area length time
• meters seconds
• m/s (meters per second)

8
S.I. Base Units

• There are a few non-SI units that we use in
  science
• volumeliters, L pressureatmospheres
  , atm
• energycalories, cal temperaturecelsius,
  C

9
Uncertainty in Measurement
Chapter 1-5

• Measurements are uncertain for two reasons
• Measuring instruments are never completely free
  of flaws
• Measuring always requires some estimation

10
Example

• When you are using a ruler or even a 4-beam
  balance, you need to estimate the last digit in
  your measurement. Heres how you do that

This line is definitely between 8 and 9 mm long.
There are also marks that arent numbered that
show 8.1, 8.2, 8.3, etc. This line looks like it
goes a little bit past the line that shows 8.4
mm, but not as far as the line that shows 8.5 mm.
We have to guess at the last number. Id say
the line is 8.41 mm long.
11

• There are two ways to check the reliability of
  your measurements
• Precision getting pretty much the same result
  every timeeven if your result is wrong
• Accuracy getting the right result
• Example
• Think about archery. Precision means getting all
  of your arrows in the same spot on the target.
  Accuracy means hitting the bulls eye.
• What could cause your measurements to be precise
  but not accurate???

12
(No Transcript)
13
Out

• Using a pencil trace a quarter, dime, nickel, and
  a penny. Measure the diameter of each coin in
  centimeters (cm). Be sure to use a decimal point
  in each of your answers.

14
In

• Compare the measurements you made of the coins
  with two people sitting near you. Explain why the
  numbers you came up with might be different.

15
Working with Numbers
Chapter 1-6

• Significant digits the certain digits and the
  one that you had to estimate

In our example with the ruler, our line measured
8.41 mm long. We were absolutely certain about
the 8 and the 4, and then we estimated the 1.
Those three numbers are all considered
significant digits.
16
How can I tell which digits are significant???

• Atlantic-Pacific Rule
• If a decimal point is Present, ignore zeros on
  the Pacific (left) side. If the decimal point is
  Absent, ignore zeros on the Atlantic (right)
  side. Everything else is significant
• Example
• 0.001010 decimal point Present ignore zeros on
  the Pacific side. (4 sig. digits)
• 12303000 decimal point Absent ignore zeros on
  the Atlantic side. (5 sig. digits)

17
Calculation Rules dealing with Significant Digits

• When a constant or conversion factor is used in a
  math problem, ignore it.
• In and , count up the number of sig. digs. in
  each number in your problem. Whichever one has
  the least, thats how many your answer will have.
• Example 127 32 4064, but 32 only has 2
  significant digits, so your answer can only have
  2. Round 4064 to 4100.

18

• In and -, you line everything up with the
  decimal. Whichever number runs out of
  significant digits first tells you where to round
  off your answer.
• Example 240
• 1523
• 25.59
• 1788.59
• However, the number 240 runs out of significant
  digits after the tens place, so you have to
  round your answer to the tens place 1788.59?1790

19

• 4. When you have a really long problem with lots
  of steps, wait until the very end to round.
  DONT ROUND AS YOU GO!!

20
Scientific Notation

• Scientific Notation basically gets rid of all
  those extra zeros on really big and really small
  measurements.
• Examples 602000000000000000000000 6.02 x 1023
  a positive exponent means the number
  used to be really big
• 0.0000000725 7.25 x 10-8 a negative
  exponent means the number used to be really small

21
How to do Scientific Notation

• Move the decimal until only one number is in
  front of the decimal. The number must be 1-9,
  not a zero.
• Take off all of the extra zeros that arent
  significant.
• Count up how many times you moved the decimal.
  That becomes your exponent.

22
Out

• Determine the number of significant digits in the
  following list of numbers
• 230.005 m 7. 0.057 g
• 109,000 kg 8. 610.0 kpa
• 328.46 mm
• 0.00607 cm3
• 5.017 L
• 8000 km

23
In

• Identify the number of significant digits in the
  following
• 0.0430 ms
• 75,800 L
• 19.007 ns
• Convert the following to scientific notation
• 4. 95,000,000
• 5. 0.0000000623

24
5 point Quiz!

• Convert the following from scientific notation
  and then identify the number of significant
  digits.
• 1.3 x 10-12 kg

25
Math in Chemistry

• Percent error tells you how far off your answer
  was the smaller your percent error, the closer
  you were to the right answer

The you got from doing the lab
The you got out of the book, off the periodic
table, from the teacher, etc.
Percent error measured value accepted value
x 100 accepted value
26
Ratios

• A ratio is a way of expressing a relationship
  between two quantities using a fraction set-up.

Heart rate beats minute
Speed distance time
Density mass volume
27
Chapter 1-7

• Dimensional analysis is a method used to convert
  a quantity with certain units into a different
  set of units.
• Example miles to meters or seconds to days

28
Unit Equalities

• A unit equality is just an equation (you must
  have an equal sign) showing how two different
  units are related.
• Examples 12 inches 1 foot
• 60 seconds 1 minute
• 1 liter 1000 cm3

29
Conversion Factors

• A conversion factor is a fraction made from a
  unit equality. For every unit equality, there
  are two possible conversion factors.
• Example 60 seconds 1 minute
• 60 seconds 1 minute
• 1 minute 60 seconds

30
Dimensional Analysis Rules

• Always start by writing the unit you are trying
  to convert.
• Figure out what unit equalities you need to get
  from the starting units to the end units, and
  turn them into conversion factors.
• Multiply your starting unit by your conversion
  factors so that units on top of the fraction go
  to the bottom and units on the bottom of the
  fraction go to the top.
• Cross out units that are on the top and the
  bottom. The only units left should be the ending
  units.

31
Example

• Convert 86 centimeters to feet.
• 86 cm
• 2.54 cm 1 inch 12 inches 1 ft2.54 cm or 1
  inch 12 in or 1 ft 1 inch 2.54 cm 1 ft
  12 in
• 3. 86 cm 1 inch 1 ft 2.8
  ft
• 2.54 cm 12 in

32
Out

• Joe got 83 points out of a possible 100 points on
  his first Chemistry test. Calculate Joes percent
  error on his exam.